Piston



H. B. GRANT.

PISTON.

APPLICATioN man OCT. 4, 1920.

l QSQ, Patented Aug. 2&9 W22.

INVENTOR: Way@ @man www@ A TT ORNE YS.

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menace.

spcification of tieners raient. I

' Application filed. october l, 1920. Serial No. 414,564. A

Tuo all it may concern-' Be it known that I, HUGO B. izen of the United States residing cago, in the county of. Cooli GRANT,a citat Chiprovements in Pistons,of whichthe .followinc* is a specification. p

his invention relates to pistons. used in internal-combustion engines, and its object is to provide the same with a novel and improved means for effecting the lubrication of the cylinder walls.

rlhe object stated is attained by means of a combination andarrangement of parts to `be hereinafter'described and claimed, andin order that the same may be better understood, reference is had to the accompanying struction of pistons of the type specified.

intermediate its ends, and in the planeof the wrist-pin bearings 7 the piston 5 has its outer surface formed with an annular depression 8 extending completely around the latter circumferentially, and at the bottom of thisdepression the same is formed into an annular oil retaining trough for grove 9 which also encircles the piston and which opens into the depression. The groove 9 extends downward and its open end points in the direction of theo-uterend or the head of the piston. Back of the groove 9, the piston wall has a plurality of ducts 10 which are inclined downwardly or in the direction of the inner end of the piston, their inner ends opening into the interior of the piston, whereas their outer ends open into the groove 9 substantially in the plane ofthe top thereof. lt will therefore be seen that when the level of the oil which collects in the roove9 reaches the top of the latter, surpl and State of lllinois, have invented new and useful lm- `rods to hollow wrist-pins,

us oil is drained back into the crank 'case by the way of the ducts 10` and the interiorof the piston. y

\ The piston hereinbefore described is designed more particularl for use in connectlon with internal-com ustion engines in whlch 011 for lubricating the cylinder walls, 1s delivered through ducts in the connecting y .the oil escaping from the latter to the cylinder Walls. The o1l escapes from the wristpin ,intol the pocket formed bythe depression 8 and runs down the same to collect inthe groove 9, from which latter surplus oil is drained back rammen nag. sa, ieee.

into the crank case through the ducts l0 as hereinbefore described. When the engine is runnlng a constant level of oil in the groove .9 is maintained, the oil filling the groove tothe topI thereof. lit will benoted that the outer side Wall of the groove 9 is beveled so that where it meets the outer surface of the piston wall, a sharp edge l1 is produced this edge being in sliding contact with the cylinder wall. On the down stroke of the piston the oil is thrown out of the groove 9 agalnst the cylinder wall, and on the upstroke the edge 1l acts to -scrape excess oil off the cylinder wall and to direct the same back into the -groo-ve. 'A ilm of oil is therefore positively deposited on the cylinder Wall, and at the 'same time the oil is prevented from escaping into the combustion chamber of the cylinder, thereby preventing or reducing toI a minimum theformation of carbon and the fouling of the spark plug from ,excess oil. A perfect lubrication ofthe cylinder is assured at all times, with the re-A sult that friction, and its attendant wear is reduced to a minimum. The piston structure also reduces compression leaks and the consumption of fuel. A further advantage of the structure resides inthe fact that the piston can be fitted closer, thereby obtaining more power and a smoother running engine. rlihe engine Will also not get as hot as where the usual type of piston is used, on account of the cutting/ down of friction by the oil constantly thrown on the cylinder walls. The groove 9 distributes the oil evenly around the cylinder wall and not only in two opposite places as is apt to be the case where the cylinder walls are lubricated by theoil discharging` thereonto directly from the hollow wrist-pins. v

l claim: v

1. A piston. of the type described comprising a hollow body provided with wristpin bearings and having in its outer surface an, annular depression completely encircllng the same circumferentially, and located 1n the plane of the wrist-pin bearings, an encircling oil-retaining groove 'at ,the bottom ofthe depression opening thereinto, and means for maintaining a constant o-il level in the groove. v

2. A piston of the type descrlbed comprising a hollow body p-rovided with wristpin bearings, and having in its outer surface an annular depression completel encircllng the same circumferentially, an located in the plane of the wrist-pin bearings, an encircling oil-retaining groove at the bottom of the depression opening thereinto, the wall of the piston having ducts communlcatlng at one end with the groove in the plane of the top thereof and at their other ends with the interior of the piston body.

3. A. piston of the type described com-.

prising a hollow body provided with wristpin bearings, and having 1n its outer surface an annular depression completely enclrcling the same circumferentially, and located in the plane of the wrist-pin bearings, and an encircling oil-retaining groove at the bottom of the depression which is closed at the bottom and opens at the top into the depression, the Wall of the piston havlng ducts communicating at one end with the `groove abo-ve the bottom thereof and at their other ends with the interior of the piston body.

4. A piston of the type described comprising a body provided with wrist-pin bearings, and having a portion intermediate its ends which is of reduced external diameter to produce an annular depression completely encirclin tially and locate in the plane of the wrist pin bearings, and said piston body at. the bottom of the depression having `an annular 'oil-retaining trough which is closed' at the bottom and opens at the top into the depression.

5. A piston of the type described comprising a hollow body provided with wrist pin bearings, and having in its outer surface an annular depression completel encircling the same circumferentially, an located in.. the plane of the wrist-pin bearings, an en# circling oil-retaining groove at the bottom of the depression opening thereinto, the outer side wall of the groove being beveled to produce a sharp ed'ge at its junction with the outer surface of the piston body, the wall of the piston having ducts communicating at one end with the groove in the plane of the top thereof and at their other ends with the interior of the piston body.

lin testimony whereof l aiix my signature. v

HUGO B. GRANT.

the body circumferen- 

